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A Short Peptide Derived from the ZorO Toxin Functions as an Effective Antimicrobial

Yuichi Otsuka1, Tomohiro Ishikawa2, Chisato Takahashi2

  • 1Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-Ku, Saitama City, Saitama 388-8570, Japan. otsukay@mail.saitama-u.ac.jp.

Toxins
|July 7, 2019
PubMed

Insights

A novel antimicrobial peptide, ALLRL, derived from Escherichia coli ZorO toxin, effectively targets Gram-positive bacteria and fungi by damaging cell membranes. This peptide shows no toxicity to mammalian cells and maintains activity in physiological salt concentrations.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Antimicrobial peptides are promising candidates for new antibiotics.
  • The ZorO toxin from Escherichia coli O157:H7 inhibits bacterial growth via an unknown mechanism.

Purpose of the Study:

  • To elucidate the inhibitory mechanism of ZorO toxin.
  • To investigate the antimicrobial potential of a specific peptide sequence (ALLRL) derived from ZorO.

Main Methods:

  • Investigated ZorO localization and its effect on E. coli plasma membrane integrity and potential.
  • Identified the essential ALLRL amino acid sequence for ZorO toxicity.
  • Tested the antimicrobial activity of synthetic ALLRL peptide against various microbes and mammalian cells.

Main Results:

  • ZorO expression in E. coli disrupts plasma membrane integrity, leading to hydroxyl radical production.
  • The five-amino acid sequence ALLRL is critical for ZorO's toxicity.
  • Synthetic ALLRL peptide exhibits antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, and Candida albicans by causing membrane damage.
  • ALLRL peptide is non-toxic to mammalian cells and retains activity in physiological salt concentrations, unlike many natural antimicrobial peptides.

Conclusions:

  • The ALLRL peptide is a potent antimicrobial agent effective against Gram-positive bacteria and fungi.
  • ALLRL represents a novel therapeutic candidate with a unique mechanism of action and favorable safety profile.
Keywords:
Toxin–Antitoxin systemZorOantimicrobial peptide

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